In Vivo Enrichment of Diabetogenic T Cells

Insights in the host response towards biomaterial-based scaffolds for cancer therapy

Immunotherapeutic strategies have shown promising results in the treatment of cancer. However, not all patients respond, and treatments can have severe side-effects. Adoptive cell therapy (ACT) has shown remarkable therapeutic efficacy across different leukaemia and lymphoma types. But the treatment of solid tumours remains a challenge due to limited persistence and tumour infiltration. We believe that biomaterial-based scaffolds are promising new tools and may address several of the challenges associated with cancer vaccination and ACT. In particular, biomaterial-based scaffold implants allow for controlled delivery of activating signals and/or functional T cells at specific sites. One of the main challenges for their application forms the host response against these scaffolds, which includes unwanted myeloid cell infiltration and the formation of a fibrotic capsule around the scaffold, thereby limiting cell traffic. In this review we provide an overview of several of the biomaterial-based scaffolds designed for cancer therapy to date. We will discuss the host responses observed and we will highlight design parameters that influence this response and their potential impact on therapeutic outcome.

Leveraging biomaterials for enhancing T cell immunotherapy

The dynamic roles of T cells in the immune system to recognize and destroy the infected or mutated cells render T cell therapy a prospective treatment for a variety of diseases including cancer, autoimmune diseases, and allograft rejection. However, the clinical applications of T cell therapy remain unsatisfactory due to the tedious manufacturing process, off-target cytotoxicity, poor cell persistence, and associated adverse effects. To this end, various biomaterials have been introduced to enhance T cell therapy by facilitating proliferation, enhancing local enrichment, prolonging retention, and alleviating side effects. This review highlights the design strategies of biomaterials developed for T cell expansion, enrichment, and delivery as well as their corresponding therapeutic effects. The prospects of biomaterials for enhancing T cell immunotherapy are also discussed in this review.

Perspectives on immunometabolism at the biomaterials interface

Productive engagement of the immune system is a persistent challenge for biomaterials scientists. Immune engineering offers a new perspective on biomaterial design, with immune cell interaction to modulate effector functions at the center. The effector functions of these cells are intimately linked to their metabolic needs and programming. Immune cell metabolism has received renewed attention in recent years, and with each new discovery there is opportunity for biomaterials scientists. This prospectus aims to provide an overview of the most recent advances in biomaterial engagement of immune cells alongside interrogation of immunometabolism, while looking to future avenues of coalescence. Four cell types are highlighted here: neutrophils, macrophages, dendritic cells, and T cells. Consideration of these two fields, and the tools within each, with a forward-looking mindset is the key to a new era of biomaterials.

Immunomodulatory Dual-Sized Microparticle System Conditions Human Antigen Presenting Cells Into a Tolerogenic Phenotype In Vitro and Inhibits Type 1 Diabetes-Specific Autoreactive T Cell Responses

Current monotherapeutic agents fail to restore tolerance to self-antigens in autoimmune individuals without systemic immunosuppression. We hypothesized that a combinatorial drug formulation delivered by a poly-lactic-co-glycolic acid (PLGA) dual-sized microparticle (dMP) system would facilitate tunable drug delivery to elicit immune tolerance. Specifically, we utilized 30 µm MPs to provide local sustained release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor β1 (TGF-β1) along with 1 µm MPs to facilitate phagocytic uptake of encapsulated antigen and 1α,25(OH)2 Vitamin D3 (VD3) followed by tolerogenic antigen presentation. We previously demonstrated the dMP system ameliorated type 1 diabetes (T1D) and experimental autoimmune encephalomyelitis (EAE) in murine models. Here, we investigated the system's capacity to impact human cell activity in vitro to advance clinical translation. dMP treatment directly reduced T cell proliferation and inflammatory cytokine production. dMP delivery to monocytes and monocyte-derived dendritic cells (DCs) increased their expression of surface and intracellular anti-inflammatory mediators. In co-culture, dMP-treated DCs (dMP-DCs) reduced allogeneic T cell receptor (TCR) signaling and proliferation, while increasing PD-1 expression, IL-10 production, and regulatory T cell (Treg) frequency. To model antigen-specific activation and downstream function, we co-cultured TCR-engineered autoreactive T cell "avatars," with dMP-DCs or control DCs followed by β-cell line (ßlox5) target cells. For G6PC2-specific CD8+ avatars (clone 32), dMP-DC exposure reduced Granzyme B and dampened cytotoxicity. GAD65-reactive CD4+ avatars (clone 4.13) exhibited an anergic/exhausted phenotype with dMP-DC presence. Collectively, these data suggest this dMP formulation conditions human antigen presenting cells toward a tolerogenic phenotype, inducing regulatory and suppressive T cell responses.

Biomaterials as Local Niches for Immunomodulation

A major function of the immune system is to detect threat from foreign invaders, tissue damage, or cancer and to mount a counter response that resolves the threat, restores homeostasis, and supplies immunological memory to prevent a second assault. Our increasing understanding of the immune system has opened up numerous avenues for modulating immune responses against infections, cancer, and autoimmunity. However, agents used for immunomodulation have been traditionally administered systemically via bolus injection, leading to unintended consequences by disrupting homeostasis at nontarget sites. Consequently, systemic hyperactivation and hypoactivation can result from bolus administration of immune-activators and immunosuppressants, respectively. Macroscale biomaterial scaffolds can instead be placed at the intended target site to provide both localized, controlled release of immunomodulatory agents and control over local immune cell trafficking and function, potentially maximizing therapeutic efficacy and limiting systemic exposure. These scaffolds have found utility in the area of cancer immunotherapy, especially in situ cancer vaccination where controlled release of factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and the local presentation of tumor antigen and danger signals lead to the recruitment of immature dendritic cells and facilitate their activation and antigen presentation. These cells eventually migrate into secondary lymphoid organs where they prime tumor specific T cells for downstream tumor clearance. Scaffolds can also be used in adoptive T cell therapy to generate large numbers of potent antigen specific T cells or chimeric antigen receptor (CAR) T cells in vitro for subsequent delivery to patients. Macroscale biomaterial scaffolds have also found utility beyond cancer immunotherapy and have been developed to promote immune tolerance by regulatory T cell induction and to expedite tissue regeneration. The design of these macroscale biomaterial scaffolds considers their biocompatibility, biodegradability, mode of delivery, porosity, and kinetics of therapeutic cargo release. Consequently, the numerous approaches that have been developed to fabricate biomaterial scaffolds are aimed at tuning these parameters to achieve the desired therapeutic outcome. This Account will discuss the use of biomaterial scaffolds as niches for immunomodulation and will focus on (1) approaches that have been used to fabricate various biomaterial systems being employed as niches for immunomodulation and (2) how these biomaterial systems have been used to modulate immune responses, specifically in area of cancer immunotherapy, where we will discuss the role of macroscale biomaterial scaffolds for in situ vaccination and in vitro T cell expansion. We will also briefly discuss the utility of biomaterial scaffolds beyond cancer, drawing examples from tolerance and tissue regeneration.

Nanotechnology and immunoengineering: How nanotechnology can boost CAR-T therapy

Chimeric antigen receptor (CAR) therapy has achieved remarkable clinical efficacy against hematological cancers and has been approved by FDA for treatment of B-cell tumors. However, the complex manufacturing process and limited success in solid tumors hamper its widespread applications, thus prompting the development of new strategies for overcoming the abovementioned hurdles. In the last decade, nanotechnology has provided sustainable strategies for improving cancer immunotherapy through vaccine development and delivery of immunomodulatory drugs. Nanotechnology can boost CAR-T therapy and may overcome the existing challenges by emerging as a carrier for CAR-T therapy or in combination with CAR-T, it may inhibit solid tumors more effectively than conventional approaches. The revealing of cellular mechanisms, barriers and potential strategies that could be used to manipulate and/or modify cells would enable unprecedented advances in nanotechnology for biologics delivery. This review outlines the journey and barriers of nanoparticles (NPs) across the cell. Subsequently, the approaches to tackle the barriers and strategies to modulate NPs as a carrier for CAR-T therapy are discussed. Finally, the role of NPs in CAR-T therapy and the potential challenges are summarized. This review aims to provide the readers with a detailed overview of NP-based CAR-T therapy research and distil this information into an accessible form conducive to design desired CAR-T therapy using NP approach. STATEMENT OF SIGNIFICANCE: Chimeric antigen receptor (CAR) T-cell therapy is the most vibrant field in immuno-oncology today, with enormous benefits to patients with B-cell malignancies. However, a rapid and straightforward procedure for CAR-T generation is an exigent need to broaden its therapeutic avenue. Nanotechnology has emerged as a novel alternative approach for CAR-T generation. To the best of our knowledge, this is the first in-depth review that briefly highlights the various aspects of nanotechnology in CAR-T therapy, including the strategies to brand NPs as an effective carrier for CAR cargo, its potential advantages, challenges, and future roadmap. It provides readers with a detailed overview of NP-based CAR-T therapy research, and researchers would be able to distill this information into an accessible form conducive to design the desired CAR therapy using the nanotechnology approach.

Antigen-specific immune decoys intercept and exhaust autoimmunity to prevent disease

Relapsing-remitting patterns of many autoimmune diseases such as multiple sclerosis (MS) are perpetuated by a recurring circuit of adaptive immune cells that amplify in secondary lymphoid organs (SLOs) and traffic to compartments where antigen is abundant to elicit damage. Some of the most effective immunotherapies impede the migration of immune cells through this circuit, however, broadly suppressing immune cell migration can introduce life-threatening risks for patients. We developed antigen-specific immune decoys (ASIDs) to mimic tissues targeted in autoimmunity and selectively intercept autoimmune cells to preserve host tissue. Using Experimental Autoimmune Encephalomyelitis (EAE) as a model, we conjugated autoantigen PLP_139-151 to a microporous collagen scaffold. By subcutaneously implanting ASIDs after induction but prior to the onset of symptoms, mice were protected from paralysis. ASID implants were rich with autoimmune cells, however, reactivity to cognate antigen was substantially diminished and apoptosis was prevalent. ASID-implanted mice consistently exhibited engorged spleens when disease normally peaked. In addition, splenocyte antigen-presenting cells were highly activated in response to PLP rechallenge, but CD3⁺ and CD19 ⁺ effector subsets were significantly decreased, suggesting exhaustion. ASID-implanted mice never developed EAE relapse symptoms even though the ASID material had long since degraded, suggesting exhausted autoimmune cells did not recover functionality. Together, data suggested ASIDs were able to sequester and exhaust immune cells in an antigen-specific fashion, thus offering a compelling approach to inhibit the migration circuit underlying autoimmunity.

Treating ischemia via recruitment of antigen-specific T cells

Ischemic diseases are a leading cause of mortality and can result in autoamputation of lower limbs. We explored the hypothesis that implantation of an antigen-releasing scaffold, in animals previously vaccinated with the same antigen, can concentrate TH2 T cells and enhance vascularization of ischemic tissue. This approach may be clinically relevant, as all persons receiving childhood vaccines recommended by the Centers for Disease Control and Prevention have vaccines that contain aluminum, a TH2 adjuvant. To test the hypothesis, mice with hindlimb ischemia, previously vaccinated with ovalbumin (OVA) and aluminum, received OVA-releasing scaffolds. Vaccinated mice receiving OVA-releasing scaffolds locally concentrated antigen-specific TH2 T cells in the surrounding ischemic tissue. This resulted in local angiogenesis, increased perfusion in ischemic limbs, and reduced necrosis and enhanced regenerating myofibers in the muscle. These findings support the premise that antigen depots may provide a treatment for ischemic diseases in patients previously vaccinated with aluminum-containing adjuvants.

Engineering Immune Tolerance with Biomaterials

Autoimmune diseases, rejection of transplanted organs and grafts, chronic inflammatory diseases, and immune-mediated rejection of biologic drugs impact a large number of people across the globe. New understanding of immune function is revealing exciting opportunities to help tackle these challenges by harnessing-or correcting-the specificity of immune function. However, realizing this potential requires precision control over the interaction between regulatory immune cues, antigens attacked during inflammation, and the tissues where these processes occur. Engineered materials-such as polymeric and lipid particles, scaffolds, and inorganic materials-offer powerful features that can help to selectively regulate immune function during disease without compromising healthy immune functions. This review highlights some of the exciting developments to leverage biomaterials as carriers, depots, scaffolds-and even as agents with intrinsic immunomodulatory features-to promote immunological tolerance.

Advances in immunotherapy of type I diabetes

Type 1 diabetes mellitus (T1DM) is an autoimmune disease affecting 3 million individuals in the U.S. The pathogenesis of T1DM is driven by immune-mediated destruction of pancreatic β cells, the source of glucose regulator insulin. While T1DM can be successfully managed with insulin replacement therapy, approaches that can modify the underlying immuno-pathology of β cell destruction has been long sought after. Immunotherapy can attenuate T cell responses against β cell antigens. Given the detailed cellular and molecular definitions of T1DM immune responses, rational immunomodulation can be and have been developed in mouse models, and in some instances, tested in humans. The possibility of identifying individuals who are predisposed to T1DM through genotyping lend to the possibility of preventive vaccines. While much has been accomplished in delineating the mechanisms of immunotherapies, some of which are being tested in humans, long-term preservation of β cells and insulin independency has not been achieved. In this regard, the drug delivery field has much to offer in maximizing the benefits of immune modulators by optimizing spatiotemporal presentation of antigens and costimulatory signals. In this review, we attempt to capture the current state of T1DM immunotherapy by highlighting representative studies.

High CD8 T-Cell Receptor Clonality and Altered CDR3 Properties Are Associated With Elevated Isolevuglandins in Adipose Tissue During Diet-Induced Obesity

Adipose tissue (AT) CD4⁺ and CD8⁺ T cells contribute to obesity-associated insulin resistance. Prior studies identified conserved T-cell receptor (TCR) chain families in obese AT, but the presence and clonal expansion of specific TCR sequences in obesity has not been assessed. We characterized AT and liver CD8⁺ and CD4⁺ TCR repertoires of mice fed a low-fat diet (LFD) and high-fat diet (HFD) using deep sequencing of the TCRβ chain to quantify clonal expansion, gene usage, and CDR3 sequence. In AT CD8⁺ T cells, HFD reduced TCR diversity, increased the prevalence of public TCR clonotypes, and selected for TCR CDR3 regions enriched in positively charged and less polarized amino acids. Although TCR repertoire alone could distinguish between LFD- and HFD-fed mice, these properties of the CDR3 region of AT CD8⁺ T cells from HFD-fed mice led us to examine the role of negatively charged and nonpolar isolevuglandin (isoLG) adduct-containing antigen-presenting cells within AT. IsoLG-adducted protein species were significantly higher in AT macrophages of HFD-fed mice; isoLGs were elevated in M2-polarized macrophages, promoting CD8⁺ T-cell activation. Our findings demonstrate that clonal TCR expansion that favors positively charged CDR3s accompanies HFD-induced obesity, which may be an antigen-driven response to isoLG accumulation in macrophages.

Biomaterial-assisted targeted modulation of immune cells in cancer treatment

The past decade has witnessed the accelerating development of immunotherapies for cancer treatment. Immune checkpoint blockade therapies and chimeric antigen receptor (CAR)-T cell therapies have demonstrated clinical efficacy against a variety of cancers. However, issues including life-threatening off-target side effects, long processing times, limited patient responses and high cost still limit the clinical utility of cancer immunotherapies. Biomaterial carriers of these therapies, though, enable one to troubleshoot the delivery issues, amplify immunomodulatory effects, integrate the synergistic effect of different molecules and, more importantly, home and manipulate immune cells in vivo. In this Review, we will analyse thus-far developed immunomaterials for targeted modulation of dendritic cells, T cells, tumour-associated macrophages, myeloid-derived suppressor cells, B cells and natural killer cells, and summarize the promises and challenges of cell-targeted immunomodulation for cancer treatment.

Identification of HLA-A2-restricted immunogenic peptides derived from Vitamin D-Binding Protein

T-cell-mediated destruction of pancreatic β cells leads to Type 1 diabetes (TID). Vitamin D-Binding Protein (VDBP) has been identified as an autoantigen and T cell reactivity against VDBP increases in the development of T1D. Autoreactive cytotoxic T lymphocytes (CTLs) recognize β-cell-derived peptides in the context of major histocompatibility complex class I molecules. However, little is known about the VDBP-derived immunogenic peptides that are presented in the context of human HLA molecules. Here, we predicted and identified VDBP derived immunogenic peptides that were presented in association with human HLA-A2 molecule. The VDBP derived peptides binding to HLA-A∗0201 were predicted by using a computer-assisted algorithm. The candidate peptides were synthesized, then affinity between peptides and HLA-A∗0201 were analyzed. In addition, the CTL activity of the peptides was detected by cytotoxicity assay and ELISPOT assay in vitro. Furthermore, HLA-A∗0201-transgenic mice were immunized with peptides to induce the CTL activity in vivo. The results demonstrated that peptides of VDBP containing residues 211-219 and 235-243 had high affinity with HLA-A∗0201. In addition, these peptides elicited potent CTL responses in vitro, and induced T1D in vivo. Therefore, this experiment identified immunogenic HLA-A∗0201-restricted epitopes derived from VDBP, and provided pathogenesis theory of T1D.

Bioengineering Solutions for Manufacturing Challenges in CAR T Cells

The next generation of therapeutic products to be approved for the clinic is anticipated to be cell therapies, termed "living drugs" for their capacity to dynamically and temporally respond to changes during their production ex vivo and after their administration in vivo. Genetically engineered chimeric antigen receptor (CAR) T cells have rapidly developed into powerful tools to harness the power of immune system manipulation against cancer. Regulatory agencies are beginning to approve CAR T cell therapies due to their striking efficacy in treating some hematological malignancies. However, the engineering and manufacturing of such cells remains a challenge for widespread adoption of this technology. Bioengineering approaches including biomaterials, synthetic biology, metabolic engineering, process control and automation, and in vitro disease modeling could offer promising methods to overcome some of these challenges. Here, we describe the manufacturing process of CAR T cells, highlighting potential roles for bioengineers to partner with biologists and clinicians to advance the manufacture of these complex cellular products under rigorous regulatory and quality control.

T Cell Receptor Profiling in Type 1 Diabetes

PURPOSE OF REVIEW

The genetic susceptibility and dominant protection for type 1 diabetes (T1D) associated with human leukocyte antigen (HLA) haplotypes, along with minor risk variants, have long been thought to shape the T cell receptor (TCR) repertoire and eventual phenotype of autoreactive T cells that mediate β-cell destruction. While autoantibodies provide robust markers of disease progression, early studies tracking autoreactive T cells largely failed to achieve clinical utility.

RECENT FINDINGS

Advances in acquisition of pancreata and islets from T1D organ donors have facilitated studies of T cells isolated from the target tissues. Immunosequencing of TCR α/β-chain complementarity determining regions, along with transcriptional profiling, offers the potential to transform biomarker discovery. Herein, we review recent studies characterizing the autoreactive TCR signature in T1D, emerging technologies, and the challenges and opportunities associated with tracking TCR molecular profiles during the natural history of T1D.

Bioengineering strategies for inducing tolerance in autoimmune diabetes

Type 1 diabetes is an autoimmune disease marked by the destruction of insulin-producing beta cells in the pancreatic islets. Strategies to delay onset or prevent the autoimmune recognition of beta cell antigens or T cell-mediated killing of beta cells have mainly focused on systemic immunomodulation and antigen-specific immunotherapy. To bridge the fields of type 1 diabetes immunology and biomaterials engineering, this article will review recent trends in the etiology of type 1 diabetes immunopathology and will focus on the contributions of emerging bioengineered strategies in the fight against beta cell autoimmunity in type 1 diabetes.